Intelligent arrangement buckle switch for seat belts

ABSTRACT

A buckle switch arrangement for a multi-point seat belt system. A restraints control module is provided to receive signals from sensors operatively associated with the vehicle seat which determine and identify seat occupancy and also to receive signals from other sensors operatively associated with the vehicle seat which sense seat belt webbing payout. The signals obtained by the restraints control module are interpreted and, based on the interpretation, a telltale device may be activated to warn the vehicle operator that a seat occupant is not in compliance with seat belt usage.

TECHNICAL FIELD

A buckle switch arrangement for seat belts is provided. The arrangementincludes a device in the nature of a Hall effect sensor coupled with theseat belt retractor for sensing the amount of seat belt extracted.Information regarding the belt payout is relayed to a module todetermine if the belt is being worn properly and may also determine if atelltale indicating non-compliance of seat belt usage or incorrect seatbelt usage should be illuminated.

BACKGROUND OF THE INVENTION

Automotive vehicles incorporate a variety of restraint systems toprovide for the safety of occupants. For example, it is known in thevehicle art to provide various types of seat belts or restraint systemsfor restraining an occupant in his or her seat and for providingcontrolled deceleration of the occupant from an event such as acollision. Various types of seat belts and restraint systems have beenused in automobiles, trucks, and other vehicles and are commonly knowntoday.

Known seat belt systems typically used in commercially availableproduction vehicles include a seat belt telltale that is visible to thedriver. The seat belt telltale is illuminated in the event that a seatbelt is not being used in 3-point seat belt systems for some time.

A commonly used telltale arrangement includes an electrical switch inthe buckle that senses engagement between the tongue or latchplate andthe buckle. This arrangement identifies the buckle status and, hence,seat belt usage. Non-compliance with seat belt usage results in a signallight being illuminated on or near the instrument cluster. Thissignaling is initiated when associated electrical information (e.g.,voltage) is transmitted using a wiring harness attached to the buckleassembly and subsequently used (e.g., by a Restraints Control Module [an“RCM”]) to determine if the telltale should be illuminated. Examples ofbuckle switch systems may be found in U.S. Pat. Nos. 4,060,878,4,163,128, 4,920,629, and 6,381,815.

An alternate method for sensing seat belt use compliance is anarrangement that is used to determine if the amount of extraction ofwebbing from the seat belt retractor is greater than a minimum amountthat would indicate seat belt usage. This is commonly done using amechanical device in the retractor which determines the number ofrevolutions of the retractor spool and hence the amount of webbingextracted. An example of this arrangement may be found in U.S. Pat. No.4,866,223.

While the above-cited references provide certain advancement in thestate of the art of systems for detecting and relaying informationrelative to seat belt use compliance, opportunities for improving suchsystems yet exist.

BRIEF DESCRIPTION

The disclosed embodiments of the invention are generally directed to abuckle switch arrangement for a multi-point seat belt system. Theembodiments are all directed to a system that determines and relays thestatus of seat belt usage. The present invention finds particularapplication with a four-point seat belt system but could also be usedwith any multi-point seat belt system using one or more retractors. Thearrangement includes an occupant seat in a vehicle, a seat beltarrangement operatively associated with the seat, at least one seat beltretractor with which at least one seat belt of the seat belt arrangementis operatively associated, and a feedback sensor associated with theseat belt retractor. The system further includes a seat occupancy sensorwhich senses occupancy of the seat. A restraints control module isprovided to receive signals from the feedback sensor and from theoccupancy sensor. The signals obtained by the restraints control moduleare interpreted by algorithmic analysis and, based on theinterpretation, a telltale device may be activated to warn the vehicleoperator that a seat occupant is not in compliance with seat belt usageor is using the seat belt incorrectly.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this invention, reference shouldnow be made to the embodiment illustrated in greater detail in theaccompanying drawings and described below by way of examples of theinvention wherein:

FIG. 1 illustrates a stylized view of the intelligent arrangement buckleswitch for seat belts as set forth herein; and

FIG. 2 is an algorithm which accompanies the arrangement of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following figures, the same reference numerals will be used torefer to the same components. In the following description, variousoperating parameters and components are described for one constructedembodiment. These specific parameters and components are included asexamples and are not meant to be limiting.

Referring to the drawings and in particular to FIG. 1, one embodiment ofa four-point seat belt restraint system, generally illustrated as 10, isshown in the donned position. A seat 12, typically for use in anautomotive vehicle (not shown), includes a generally upright seat back14 extending between a top portion 16 and a bottom portion 18 forsupporting the back of a seated occupant. The seat 12 further includes agenerally horizontal seat cushion 20 projecting forwardly from thebottom portion 18 of the seat back 14 and extending between an inboardor right side 22 and an outboard or left side 24 for supporting thebottom of the seated occupant. The inboard, side 22 is further definedby the side of the seat 12 adjacent the inboard or middle of the vehicleand the outboard side 24 is further defined by the side of the seat 12adjacent the outboard or outside of the vehicle as is commonly known inthe art.

The four-point seat belt restraint system 10 includes a first, orinboard shoulder belt webbing 26 extending from the top portion 16 tothe bottom portion 18 of the seat back 14 adjacent the inboard side 22of the seat cushion 20. The four-point seat restraint system 10 furtherincludes a second, or outboard, shoulder belt webbing 28 extending fromthe top portion 16 to the bottom portion 18 of the seat back 14 adjacentthe outboard side 24 of the seat cushion 20. The four-point seat beltrestraint system 10 further includes a first, or inboard, lap beltwebbing 30 extending from the inboard side 22 of the seat cushion 20 toa buckle/tongue 32 (which may be either a tongue or a buckle) and asecond, or outboard, lap belt webbing 34 extending from the outboardside 24 of the seat cushion 20 to a tongue/buckle 36 (which may beeither a buckle or a tongue). The first lap belt webbing 30 is anchoredto the seat 12 by a retractor 38 having a retractor spool 39. Theretractor 38 is anchored to the seat by fasteners including bolts, weldsand the like. The second lap belt webbing 34 is anchored to the seat 12by a retractor 40, also attached to the seat 12 by the mentionedfasteners. The retractor 40 includes a spool 41. When the first shoulderbelt webbing 26, the second shoulder belt webbing 28, the first lap beltwebbing 30, and the second lap belt webbing 34 are donned and thebuckle/tongue 32 and the tongue/buckle 36 are attached, the assembledbuckle/tongue 32 and tongue/buckle 36 are ideally located across thecenterline of the occupant (not shown).

In particular, the lap belt retractors 38 and 40 (as well as theshoulder belt retractors) may even be attached to the body structure inso-called body mounted systems. The present invention easily extendssuch a body mounted system if additionally a sensor 43 may be providedto measure fore and aft seat travel (if the seat is movable). Thisinformation is processed together with the lap retractor webbinginformation to determine occupant presence and the like.

The retractors 38 and 40 may be positioned in a variety of placesrelative to the seat 12, but are shown herein in their preferredpositions substantially under the seat 12. The illustrated under-seatlocation of the lap belt retractors 38 and 40 under the seat makespackaging of the retractors easier and more economical, particularly invehicles where seat-to-tunnel or seat-to-door spacing is restricted.

While two retractors 38 and 40 are illustrated it is to be understoodthat a single retractor may be used in lieu of the shown and discussedpair. Conversely, the retractors 38 and 40 may be substituted for by arigid, fixed anchor as is known in the art. The retractors 38 and 40 maybe of a variety of types, including mechanical, mechanical with electricretractor, electromagnetic, and others. An electric retractor isvaluable in that it offers a selected tension (either constant orvarying) to be imposed on the lap belts 30 and 34 to aid in maintainingthe buckle/tongue 32 and the tongue/buckle 36 as low on the occupant'slap as possible. In addition, a high lap belt tension also resistslateral motion of the lap belts 30 and 34, thereby assisting inmaintaining the buckle-tongue interface of the buckle/tongue 32 and thetongue/buckle 34 as close to the centerline of the occupant as ispossible. This arrangement offers an improvement over known restraintsystems using conventional mechanical retractors. The retractors 38 and40 may also be equipped with dynamic pretensioners (of the pyrotechnictype or of another design). The retractors 38 and 40 also may beequipped with static; pretensioning.

The first shoulder belt webbing 26 is releasably attachable to thebuckle/tongue 32 and the second shoulder belt webbing 28 is releasablyattachable to the tongue/buckle 36. The buckle/tongue 32 is releasablyattachable to the tongue/buckle 36. This arrangement results in theillustrated V-shape defined by the substantial convergence of the firstshoulder belt webbing 26 and the second shoulder belt webbing 28 at thebuckle/tongue 32 and the tongue/buckle 36. The first shoulder beltwebbing 26 and the second shoulder belt webbing 28 have a large lateralspacing as illustrated from the occupants neck (not shown) while stillproviding effective support by the convergence along the centerline ofthe occupant at the area of the buckle/tongue 32 and the tongue/buckle36. This increased lateral spacing at the upper part of the seat 12increases occupant comfort for occupants of different sizes, includingsmaller occupants having smaller necks, narrower shoulders and shorterupper torso eights. This geometry also aids in keeping seat belts on theoccupant's shoulders at all times, while lowering the risk of softtissue neck injury and enhancing comfort for wide range of occupantbuilds.

It is to be understood that the buckle arrangement illustrated in FIG. 1may be altered so that, for example, the buckle component is provided onthe shoulder webbing. The configuration shown is intended as beingillustrative and not limiting.

The first shoulder belt webbing 26 and the second shoulder belt webbingmay be anchored to the seat 12 by separate or a single retractor(neither shown) fixedly secured to the seat 12 by fasteners includingbolts, welds and the like. Alternatively, the retractor may be mountedon the body as in known body-mounted systems.

The restraint system 10 is fitted with an occupant sensing andidentification system for determining whether or not the seat 12 isoccupied. The occupant sensing and identification system also functionsto determine whether the occupant is a child in a Child Restraint Seat(CRS). The occupant sensing and identification system includes a firstof two occupant sensing and identification sensors 42 operativelyassociated with the seat 10. The occupant sensing and identificationsystem further includes a second of two occupant sensing andidentification sensors 44 also operatively associated with the seat 10.When activated, the first occupant sensing and identification sensor 42and the second occupant sensing and identification sensor 44 provide anelectrical signal to an Occupant Classification System (OCS) unit 46 viaa first conduit 48 connected between the first occupant sensing andidentification sensor 42 and the OCS unit 46 and via a second conduit 50connected between the second occupant sensing and identification sensor44 and the OCS unit 46. The OCS unit 46 then analyzes the receivedelectrical signal and, if appropriate, sends a corresponding electricalinput signal of a sufficient and pre-established value to a RestraintsControl Module 52 which interprets the information received from the OCSunit 46 and generates, if appropriate, an electrical signal to atelltale device 54 as will be discussed in greater detail below. Thetelltale device 54 may produce a visual signal, an audio signal, orboth.

The restraint system 10 is further fitted with a sensor arrangement todetermine if the webbing of the retractors 38 and 40 have been paid out.Particularly, a payout sensor 56, such as an electromagnetic e.g.,optical or electrical, mechanical or even possibly chemical sensor, isfitted to the retractor 38. A similar or same payout sensor 58 is fittedto the retractor 40. The sensors 56 and 58 monitor the webbing payoutfrom each of the retractors 38 and 40, respectively. Electrical inputsignals (for example, current in mA) are sent to the Restrains ControlModule (RCM) 52 by way of a first electrical conduit 60 and a secondelectrical conduit 62, the first electrical conduit 60 being associatedwith the retractor 38 and the second electrical conduit 62 beingassociated with the retractor 40. The RCM 52 then interprets theinformation received from the payout sensors 56 and 58. Once theinformation is interpreted, the RCM 52 generates, if appropriate, anelectrical signal to a telltale device 54.

The RCM 52 uses an algorithm to determine whether or not the telltaledevice 54 should be activated. While a number of related algorithms maybe used to determine the nature of the seat belt usage, a preferredalgorithm to effect this purpose is set forth in FIG. 2. According tothis algorithm, the initial inquiry is whether or not the ignition ofthe vehicle is on. If the ignition is not on, then no signal is sent tothe telltale device 54. If the ignition is on, then an inquiry is madewhether or not an occupant is present, as sensed by the sensors 56 and58 and as interpreted by the OCS 46. In the event that it is determinedthat no occupant is present, then no signal will be sent to the telltaledevice 54.

Is an occupant present? If it is determined that an occupant is presentin the seat, then two inquiries are made, both with respect to whetheror not the lap belt webbing has been extracted far enough from theretractor to confirm proper seat belt utilization.

Is the occupant an adult or a child? If the determination is “yes” thentwo further inquires will be made. One inquiry is whether or not a childrestraint seat (CRS) is present with a child seated therein. If theanswer is “yes,” then no signal will be sent to the telltale device 54.If, however, the answer is “no” (indicating that a child restraint seatis present but the seat is unrestrained), then an activation signal willbe sent to the telltale device 54.

The other inquiry is whether or not the webbing from the lap beltretractor has been withdrawn far enough to confirm that the seat beltis, in fact, being properly used. If the answer to this is “yes” and ifthe difference in the length of belt webbing exhausted from eachretractor is less than or equal to a predetermined amount (for example,2.0″), then no signal will be generated. If, on the other hand, theanswer to the first question is “yes” and the difference in extractedbelt webbing is greater than the predetermined amount, then a signalwill be generated.

If, however, the answer to the original inquiry (regarding thesufficiency of webbing length extracted from the lap belt retractor) is“no,” then an activation signal will be sent to the telltale device 54.

The possible conditions (other than the ignition being “off”) aresummarized in Table 1. The algorithm is used to determine the followingclassifications:

(1) no occupant

(2) occupant (not in CRS) buckled, with buckle in proper position(correct zone)

(3) occupant (not in CRS) buckled, with buckle out of zone

(4) occupant (not in CRS) not buckled

(5) occupant in restrained CRS

(6) occupant in unrestrained CRS

In the event that conditions (3), (4), or (6) exist, the RCM 52 willsend an activating signal to the telltale device 54. In the event thatconditions (1), (2) or (5) are determined to exist, no such signal willbe sent.

TABLE 1 Child seat (with child)? Buckle Occupant? Seatbelt (sensedwithin Condition Description (sensed by OCS) “buckled”? by OCS) zone?Telltale 1 No occupant N Y/N N Y/N Off 2 Occupant Y Y N Y Off (not inCRS) buckled, with buckle in zone 3 Occupant Y Y N N On (not in CRS)buckled, with buckle out of zone 4 Occupant Y N N N/A On (not in CRS)not buckled 5 Occupant in Y Y Y Y/N Off restrained CRS 6 Occupant in Y NY N/A On unrestrained CRS 7 Occupant in Y N Y N/A On booster 8 Occupantin Y Y Y N On booster 9 Occupant in Y Y Y Y Off booster NOTE 1: Aboveassumes “Ignition On”. For the trivial case, of “Ignition Off” thetelltale will be “OFF” NOTE 2: Above also assumes that if webbing>L_(crit) is pulled out of either retractor => “buckled” state. NOTE: 3:“Null” signal treated as “No” NOTE 4: Assume whenever a CRS is present,it is restrained by the seatbelt system. Hence a typical booster seatwould not be treated as a CRS by this algorithm.

According to the present invention, a solution to known problemsassociated with non-compliance with seat belt usage requirements ispresented in an efficient and cost-effective manner. The vehicleoperator will immediately know if a passenger is not wearing a seatbeltor if a passenger is wearing a seat belt but the seat belt buckle isoutside of the preferred zone for effective wearing. The presentinvention also provides information to the vehicle operator as towhether or not a child is in an unrestrained child restraint seat.

1. A system for determining and relaying the status of seat belt usage,the system comprising: a seat; a seat belt arrangement operativelyassociated with said seat; a seat belt retractor, said seat beltarrangement being operatively associated with said seat belt retractor;a belt webbing operatively associated with said seat belt retractor; afeedback sensor operatively associated with said seat belt retractor,said feedback sensor being responsive to payout of said belt webbingfrom said retractor.
 2. The system for determining and relaying thestatus of seat belt usage of claim 1, wherein said seat belt retractorincludes a rotatable retractor spool to which said belt webbing isattached and wherein said feedback sensor senses rotation of saidrotatable retractor spool.
 3. The system for determining and relayingthe status of seat belt usage of claim 1, wherein said feedback sensorsenses webbing payout by way of a signal selected from the groupconsisting of electromagnetic, mechanical or chemical signals.
 4. Thesystem for determining and relaying the status of seat belt usage ofclaim 3, wherein said seat belt arrangement further includes a lap belt.5. The system for determining and relaying the status of seat belt usageof claim 4, wherein said lap belt includes a retractor.
 6. The systemfor determining and relaying the status of seat belt usage of claim 5,wherein said retractor includes a feedback sensor.
 7. The system fordetermining and relaying the status of seat belt usage of claim 1,further including a restraints control module, said feedback sensorbeing operatively associated with said restraint control module.
 8. Thesystem for determining and relaying the status of seat belt usage ofclaim 7, further including a telltale indicator, said telltale indicatorbeing operatively associated with said restraint control module.
 9. Thesystem for determining and relaying the status of seat belt usage ofclaim 6, wherein the system is incorporated into a vehicle housing orignition system and a telltale indicator, the system further includingan algorithm associated with said feedback sensor for determining thenature of seat belt usage, the algorithm including the steps ofdetermining if the vehicle ignition is on, determining if an occupant ispresent in the seat, determining if payout of said lap belt meet apre-determined critical amount, and determining if the telltaleindicator should be illuminated.
 10. The system for determining andrelaying the status of seat belt usage of claim 1, further including aseat occupancy sensor operatively associated with said seat.
 11. Thesystem for determining and relaying the status of seat belt usage ofclaim 1, wherein said seat belt retractor is attached to said seat. 12.The system for determining and relaying the status of seat belt usage ofclaim 1, wherein the system includes a support structure adjacent tosaid seat and wherein said retractor is attached to said adjacentsupport structure.
 13. A system for determining and relaying the statusof seat belt usage in a mode of transportation which includes a seat, anignition system, and a telltale indicator, the system comprising: a seatbelt arrangement operatively associated with the seat, said seat beltarrangement including at least one seat belt; a seat belt retractor,said seat belt retractor being operatively associated with said at leastone seat belt; and a sensor system being operatively associated withsaid seat belt retractor, said sensor system including an algorithm anda restraint control module, the algorithm including the steps ofdetermining if the ignition is on, determining if an occupant is presentin the seat, determining if seat belt payout of said at least one seatbelt from said retractor meets a pre-determined critical amount, anddetermining if the telltale indicator should be illuminated.
 14. Thesystem for determining and relaying the status of seat belt usage ofclaim 13, in which said sensor system includes a seat occupancy sensoroperatively associated with the seat to determine if an occupant ispresent in the seat.
 15. The system for determining and relaying thestatus of seat belt usage of claim 13, in which said sensor systemincludes a feedback sensor for sensing the payout of said seat belt. 16.The system for determining and relaying the status of seat belt usage ofclaim 15, wherein said seat belt arrangement further includes at leastone lap belt and wherein said at least one lap belt includes one of saidretractors.
 17. The system for determining and relaying the status ofseat belt usage of claim 16, wherein said retractor includes saidfeedback sensor.
 18. The system for determining and relaying the statusof seat belt usage of claim 13, wherein said sensor system furtherincludes a restraints control module.
 19. The system for determining andrelaying the status of seat belt usage of claim 18, further including atelltale indicator, said telltale indicator being operatively associatedwith said restraint control module.
 20. A method for determining whetheran occupant of a seat in a transportation mode is using a seat belt andfor conveying information related to seat belt usage, the method,comprising the steps of: forming a seat and a seat belt, said seat beltincluding a retractor, said retractor having a feedback sensor forsensing the payout of said seat belt from said retractor determining ifthe ignition system of the transportation mode is on; determining if anoccupant is in the seat; determining if the amount of payout of saidseat belt from said retractor has met a pre-determined critical stage;and determining whether or not a telltale should be engaged based uponwhether or not the amount of payout has met said pre-determined criticalstage.